QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9md

Earthquake near Loíza, PR

No earthquake was likely felt in Loíza in the 24 hours to 6:02 pm AST (22:02 UTC). The last one was M 4.1, 78 km (48 mi) SE, at 5:44 am AST on 28 October 2026, estimated intensity II (weak) in town; 5 felt reports to USGS. Every earthquake near Loíza

This page: a magnitude 2.9 earthquake was recorded 24 km (15 mi) north of Loíza, PR, at 9:53 am AST on 3 April 2021 (13:53 UTC), 65 km deep. 1 person has reported feeling it to USGS.

USGS: 23 km N of Loíza, Puerto Rico

34 km (21 mi) NE of San Juan, PR · 28 km (18 mi) NNE of Carolina, PR

9:53 am AST, Apr 3, 2021 · · 65 km deep · released about 630 lb of TNT

Every earthquake near Loíza Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Loíza Municipio 23 kmCarolina Municipio 29 kmRío Grande Municipio 30 kmSan Juan Municipio 33 kmLuquillo Municipio 35 kmCanóvanas Municipio 35 kmCataño Municipio 37 kmTrujillo Alto Municipio 37 kmToa Baja Municipio 40 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
9:53 am AST on 3 April 2021 ()
Where
24 km (15 mi) north of Loíza, PR · earthquakes near Loíza
Magnitude
M 2.9 (md)
Depth
65 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Loíza Municipio, 23 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1556 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Loíza, 24 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Earthquakes near other towns within 30 km: Suárez, Vieques, San Isidro, Santa Barbara, Río Grande, La Dolores.

How big was it?

This earthquake released about 630 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 24,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 17,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.5× the energy of this one
  4. This earthquake M 2.9 about 630 lb of TNT

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 18.6430, -65.8658. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Loíza Municipio, PR 23 km (15 mi) SSW earthquakes near Loíza Municipio
Carolina Municipio, PR 29 km (18 mi) SSW earthquakes near Carolina Municipio
Río Grande Municipio, PR 30 km (19 mi) SSE earthquakes near Río Grande Municipio
San Juan Municipio, PR 33 km (20 mi) SW earthquakes near San Juan Municipio
Luquillo Municipio, PR 35 km (22 mi) SSE earthquakes near Luquillo Municipio
Canóvanas Municipio, PR 35 km (22 mi) S earthquakes near Canóvanas Municipio

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

27 earthquakes have been recorded within 50 km since this one.

  1. 3.1 4 km NNW of Levittown, Puerto Rico
  2. 3.1 Puerto Rico region
  3. 3.2 60 km N of Loíza, Puerto Rico
  4. 2.4 3 km SSE of Pájaros, Puerto Rico
  5. 2.7 71 km NNE of San Juan, Puerto Rico
  6. 3.3 1 km ESE of Guaynabo, Puerto Rico
  7. 3.6 0 km W of Canovanas, Puerto Rico
  8. 3.4 28 km NNE of Vieques, Puerto Rico
  9. 3.5 54 km NNE of Luquillo, Puerto Rico
  10. 3.6 2 km ESE of Pájaros, Puerto Rico
  11. 2.9 47 km N of Suárez, Puerto Rico
  12. 3.0 2 km SW of Canovanas, Puerto Rico
  13. 2.7 0 km NW of Aguas Buenas, Puerto Rico
  14. 3.4 23 km NNE of Fajardo, Puerto Rico
  15. 2.8 12 km N of San Juan, Puerto Rico

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.